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Allowable Stress for Pipe Spec API 5L Gr. X42 - 1966

Allowable Stress for Pipe Spec API 5L Gr. X42 - 1966

Allowable Stress for Pipe Spec API 5L Gr. X42 - 1966

(OP)
Does anyone know the allowable stress, S, for Pipe Spec API 5L Gr. X42 per ANSI B31.3-1966.  I am probably going to have to rerate an old pipeline after inspection in accordance with its original allowable stress.  Thank you in advance.

RE: Allowable Stress for Pipe Spec API 5L Gr. X42 - 1966

XNN Grade would mean NN denotes the yield stress in 1000 lb/in2, or PSI/1000, if you will, hence the Maximum Allowable Stress for a Gr. X42 Pipe would be 42,000 psi / Area Class Safety Factor (a factor between 0.4 to 0.72) of the area classification in which it was installed.

BigInchworm-born in the trenches.
http://virtualpipeline.spaces.msn.com

RE: Allowable Stress for Pipe Spec API 5L Gr. X42 - 1966

Sorry,

You said B31.3

I gave you the allowable stress for B31.4 or 8 pipeline codes.  I think the allowable stress for X42 under B31.3 was/is 20 ksi, but wait for confirmation.

BigInchworm-born in the trenches.
http://virtualpipeline.spaces.msn.com

RE: Allowable Stress for Pipe Spec API 5L Gr. X42 - 1966

B31.3 doesn't give you credit for 42,000 psi Yield Strenght or X42 pipe, you'll have to use 20,000.

RE: Allowable Stress for Pipe Spec API 5L Gr. X42 - 1966

I couldn't get this off my mind.  Its been bothering me for an hour now.  Now I know what it was that has been bugging me.

1.)  Why was a PIPELINE built to B31.3?  
2.)  Its very unusual to use X grade material in B31.3 construction, since as decastro mentioned, there is no credit for the extra strength, so X GRADE its a waste of good money.

Those resons make me think that the pipeline was not built to B31.3, but B31.4 if liquid, or B31.8 if gas.  I recommend you do some in depth "digging" and confirm the code under which it was constructed was indeed B31.3.  I think it might not have been 31.3.

Lastly, if you want to rerate, why not recode as well?  If it is a pipeline, rerate it under the proper code.  If it is a regulated pipeline in the U.S., the design and construction must conform to CFR Title 49 Part 192 or 194 (based on B31.4/8), so if rerated and/or operated under B31.3, you may face some nonconformities.  Hay, its worth a phone call or two.

BigInchworm-born in the trenches.
http://virtualpipeline.spaces.msn.com

RE: Allowable Stress for Pipe Spec API 5L Gr. X42 - 1966

BigInch, there was no DOT in 1966 and a lot of chemical plants built their own lines with plant engineers, not pipeliners.  I up'd the MAOP on a liquid line from 1440 to 1650 psi (changed out flanges) that was in that situation.  

Cpinner, let us know how it turns out.

RE: Allowable Stress for Pipe Spec API 5L Gr. X42 - 1966

Re-rating an old pipeline is not my forte, but can you not hydrotest it according to 31.8 or 31.4 (after inspection) and rate it accordingly?  

If it has class 300 fittings and holds a strength test, would it not be rated to 740 psi?

Greg Lamberson, BS, MBA
Consultant - Upstream Energy
Website: www.oil-gas-consulting.com

RE: Allowable Stress for Pipe Spec API 5L Gr. X42 - 1966

dcastro,

You are so right.  No DOT, DOE... even Medicare, right?  Big brother wasn't so big back then.

OK, that aside, today there would be no need to rerate using B31.3 if this pipe is indeed a "pipeline".  If its a regulated DOT pipeline, it would even be inappropriate, as B31.3 does not address many factors of pipeline design...Area Class Factors for example.

CPinner,

Have a look at the Scope paragraphs of the codes and determine if your "pipeline" falls under the definition of "Pipeline" or some other facility.

BigInchworm-born in the trenches.
http://virtualpipeline.spaces.msn.com

RE: Allowable Stress for Pipe Spec API 5L Gr. X42 - 1966

CPinner,
The design allowable stress per B31.3 is 20 ksi. In terms of rerating, 49 CFR may well apply if pipeline is in the USA, in which case you must use the requirements therein.

RE: Allowable Stress for Pipe Spec API 5L Gr. X42 - 1966

(OP)
The pipeline built to API 5L-X42 is buried on the property of an operating plant.  All piping in the plant is built to ASME B31.3 as a minimum.  The few drawings that I could find on this pipeline are dated 1967 and that is why I am looking for allowable stress values per ANSI B31.3-1966.  I understand that B31.3 is the more conservative approach.  I appreciate all of your comments and will look into all suggestions/recommendations.  If someone finds a copy of B31.3-1966 please let me know.

RE: Allowable Stress for Pipe Spec API 5L Gr. X42 - 1966

CPinner,
The Houston, TX Main Library is an excellent resourse for old Codes and ASTMs. I have obtained specs from the 1940s there and the librarians have been very helpful.

RE: Allowable Stress for Pipe Spec API 5L Gr. X42 - 1966

You will find that the 1966 version of B31.3 will show 20ksi. It doesn't matter though.  You have documents (and I hope you get 1 or 2 pieces sent to a lab to confirm this ) that the pipe is 5L-X42.  NOW, as operator of the plant you can chose any standard you want for the buried pipe.  Call it plant piping B31.3 with the equations and corrosion allowance you select and 20ksi.  You can call it a liquid line under B31.8 witha .72 design factor at 42ksi, or you can call it a gas line under B31.8 with a design factor of .4 to .72 depending on how you want to classify the location.  Its all your choice as operator.

For example a 6" sch40 could be anywhere from 1205 to 2130 MAOP (from my quickie tables).

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